1. Field of the Invention
The present invention relates to an image processing apparatus and method.
2. Description of the Related Art
On an image processing apparatus such as a printer, various kinds of data processing are performed on image data to be printed. In addition, data compression and decompression are performed on the image data. In those cases, either a page mode or a band mode is used. In the page mode, data processing is performed on image data stored on a page basis. The band mode is a mode of performing the data processing on the image data that is stored on a band data basis. Note that the band data is obtained by dividing one page of image data into a plurality of bands of image data.
On one image processing apparatus, the page mode or the band mode is selected based on a size of a page memory and a size of bitmap data obtained based on the image data.
However, on the above-described image processing apparatus, it is necessary to calculate the size of the bitmap data based on the image data when selecting the page mode or the band mode. Therefore, when the image data is supplied to the image processing apparatus, it is difficult to immediately start the data processing on that image data.
Alternatively, on another image processing apparatus, when a plurality of data processings are sequentially performed on band data, the band data is subjected to a given data processing, and then a data processing at the subsequent stage is performed on that band data. Therefore, the band data for which the data processing has been performed is stored in a memory, after which the band data is read from the memory in the data processing at the subsequent stage. In a case where the plurality of data processings are sequentially performed on the band data, the band data is temporarily stored in the memory, which requires a long period of time for writing and reading the band data.
Further, on the above-described image processing apparatus, an image rendering apparatus and a compressor/decompressor use one memory controller to perform writing and reading of data to and from an image memory, and hence a load thereon is likely to increase, and a period of time for the writing and reading tends to be longer.